The broad, long-range objective of this proposal is to improve the prognosis for patients with hepatocellular carcinoma (HCC). HCC is a major global burden of morbidity and mortality and its incidence in the US has tripled over the past 30 years. Locoregional thermal ablative therapies are important treatment options for early-mid stage HCC, achieving short-term outcomes similar to surgery with less morbidity. However, high tumor recurrence rates after treatment of larger HCCs (up to 75% at 5 years) limit their applicability and overall survival remains poor for these patients. Of significant concern, there is evidence that thermal ablation of HCC may induce further malignant progression. Development of therapeutic strategies for improving the efficacy of thermal ablation and ultimately patient prognosis will require a greater understanding of the molecular mechanisms regulating thermal resistance, recurrence and tumor progression. We have identified a critical role for heat stress induced MET and EGFR receptor tyrosine kinase (RTK) mediated PI3K-AKT survival signaling in HCC thermal resistance and progression and are especially excited about the observation that inhibition of the PI3K-AKT-mTOR pathway thermosensitizes HCC and accelerates heat stress induced cell killing. The specific aims of this proposal are: 1) To determine mechanisms of heat stress induced MET/EGFR-PI3K-AKT signaling regulating HCC molecular thermoresistance; 2) To determine mechanisms of thermal ablation induced tumor progression; 3) To modulate HCC sensitivity to thermal ablation by PI3K-AKT-mTOR inhibition. We will use a combination of cellular and molecular methods, novel imaging techniques and in vitro, in vivo and patient-based approaches to systematically investigative the mechanistic role of the novel heat stress induced MET/EGFR-PI3K-AKT axis in HCC thermoresistance and tumor progression. Successful completion of these studies will increase our understanding of the mechanisms of molecular thermal ablation induced resistance and tumor progression and provide a strong scientific framework for translating a mechanism- based combination ablative therapy for HCC to early stage clinical trials. Overall, this proposal is potentially of high impac given lack of effective long-term treatments for HCC. The findings from this research will also likely be generalizable to other solid organ malignancies treated with thermal ablation because of the known dysregulation of RTKs, PI3K-AKT pathway, and growth factors in other tumors.